We plan to isolate intact interphase chromosomes from the synchronous plasmodium of Physarum polycephalum, and examine the molecular interactions that constrain the DNA in a folded conformation. We will determine the physical properties of the folded chromosomes by sedimentation and viscosity measurements. We will analyze the macromolecules (histone proteins, non-histone proteins, RNA) associated with the folded DNA, and study their role in chromosome structure. The properties of chromosomes in S phase and G2 will be compared with each other and with the properties of the condensed mitotic chromosomes. We shall probe into the mechanism of chromosome condensation and cell division, a basic foundation from which we may begin to understand the nature of abnormal cancer growth.